1. Technical Field
The present invention relates to an optical article containing a layer of which main component is SiO2 (silicon dioxide) and a manufacturing method thereof.
2. Related Art
Generally, on a surface of an optical article such as a spectacle lens, a hard coat layer to prevent abrasion, an anti-reflection layer to prevent ghost and flicker, an anti-dirt layer to provide water- and oil-repellent effects and the like are provided.
The anti-reflection layer is generally structured by a plurality of layers formed by alternately laminating materials having different refractive indices on a surface of the hard coat layer. Regarding materials to form such a multilayered anti-reflection layer, JP-A-2003-329803 discloses a technology in which SiO2 is used as a low refractive index layer while ZrO2 (zirconium oxide), TiO2 (titanium oxide), Nb2O5 (niobium oxide) or the like is used as a high refractive index layer.
However, since the hardness of SiO2 that is used as the low refractive index layer of the anti-reflection layer is lower than the hardness of ZrO2, abrasion resistance of the optical article formed by a combination of the disclosed materials is low. Accordingly, the optical article may be abraded due to rough handling by a user or carelessness of the user. Further, the abrasion may cause a film detachment.